Advances in medical technology are enabling doctors to identify and treat injuries that went unnoticed 20 years ago. For example, physicians can now use miniaturized television cameras to see inside a joint. With this tool, they have been able to identify and treat a shoulder injury called a glenoid labrum tear.
The shoulder joint has three bones: the shoulder blade (scapula), the collarbone (clavicle), and the upper arm bone (humerus). The head of the upper arm bone (humeral head) rests in a shallow socket in the shoulder blade called the glenoid. The head of the upper arm bone is usually much larger than the socket, and a soft fibrous tissue rim called the labrum surrounds the socket to help stabilize the joint. The rim deepens the socket by up to 50% so that the head of the upper arm bone fits better. In addition, it serves as an attachment site for several ligaments.
Injuries to the tissue rim surrounding the shoulder socket can occur from acute trauma or repetitive shoulder motion. Examples of traumatic injury include:
- Falling on an outstretched arm
- A direct blow to the shoulder
- A sudden pull, such as when trying to lift a heavy object
- A violent overhead reach, such as when trying to stop a fall or slide
- Shoulder dislocation or subluxation
Throwing athletes or weightlifters can experience glenoid labrum tears as a result of repetitive shoulder motion.
The symptoms of a tear in the shoulder socket rim are very similar to those of other shoulder injuries. Symptoms include
- Pain, usually with overhead activities
- Catching, locking, popping, or grinding
- Occasional night pain or pain with daily activities
- A sense of instability in the shoulder
- Decreased range of motion
- Loss of strength
If you are experiencing shoulder pain, your doctor will take a history of your injury. You may be able to remember a specific incident or you may note that the pain gradually increased. The doctor will do several physical tests to check range of motion, stability, and pain. In addition, the doctor will request x-rays to see if there are any other reasons for your problems.
Because the rim of the shoulder socket is soft tissue, x-rays will not show damage to it. The doctor may order a computed tomography (CT) scan or magnetic resonance imaging (MRI) scan. In both instances, a contrast medium may be injected to hel